Lower intraluminal thrombus load in patients with abdominal aortic aneurysms and blood type O

Abdominal aortic aneurysm (AAA) is a major cause of mortality among older men. Current clinical practice primarily determines the indication for elective AAA repair based on the maximum aneurysm diameter. However, this approach may not adequately capture the complexity of individual rupture risk, and intraluminal thrombus (ILT) has been associated with increased growth and rupture risk. In other vascular beds, non-O blood types are correlated with an increased risk of thrombosis. This study investigates the association between ABO blood type and ILT volume in AAA patients.

A cross-sectional analysis of patients with infrarenal AAAs from the Copenhagen Aortic Cohort (COACH) assessed AAA diameter, AAA volume, and ILT volume using three-dimensional ultrasound and 3D-CEUS, respectively. Patients were categorized into blood type O and non-O groups for analysis. ILT volume was compared between the groups.

In total, 296 patients under surveillance for AAA with a median AP diameter of 43 [IQR 38-48] mm, and blood type O (N.=101) and non-O (N.=195) were included. Patients with blood type O had a 4.6% lower ILT volume per 10 mL AAA volume than patients with other blood-types (P=0.003), after adjusting for AAA volume and other known covariates.

Blood type O is associated with a lower thrombus load in patients with AAA. This finding aligns with prior evidence linking non-O blood types to elevated vWf and Factor VIII levels, both important in generating thromboses. Future longitudinal studies are needed to explore the relationship between blood type and AAA progression.